Mike Nolan said he wanted to refrain from raiding pet players from his former team. But when the new 49ers coach saw former Ravens defensive end Marques Douglas lingering on the free-agent market, he couldn't resist.

The 49ers signed Douglas to a three-year deal Thursday.

"I needed to make an exception to the rule," said Nolan, the Ravens' former defensive coordinator, during a conference call.

Douglas, at 6-foot-2 and 290 pounds, has the girth and knowledge to man the right defensive-end spot in the 49ers' newly fashioned 3-4 defense.

"I felt at ease when I saw that we are running the same defense we ran in Baltimore," Douglas said. "The language and everything is the same, so I felt right at home. They've added some things to keep teams on their toes. Everyone assured me that the team is moving in a positive direction and that they're building. I want to be one of the blocks to be put in the building."

A starter for the last two seasons, Douglas had 72 tackles and 5 1/2 sacks last season.

Nolan figured that Douglas could help set the tone with the Niners, particularly on defense.

"He will help with work ethic," Nolan said. "We already have a pretty good work ethic, but this is just the beginning of this thing."

Next up for Nolan and the 49ers is choosing a player with the first overall pick in the April 23-24 draft. For now, the candidates have been narrowed to Utah quarterback Alex Smith, Cal quarterback Aaron Rodgers, Michigan wide receiver Braylon Edwards and Miami cornerback Antrel Rolle.

The four prospects will be in for all-day visits next week, and the team will begin contract negotiations on a preliminary basis with all four next week as well.

Ability to sign the players will have some bearing on who's chosen.

"It could be a factor to some degree," Nolan said. "How much is difficult to say."

The contract issue pales in comparison to character, according to Nolan, who would clean out a room in his house and have all four move in if he could.

"If I could meet with them every day that would be great," Nolan said.